Let's agree to this: the Nikon is less expensive, but also worse in terms of light gathering power, and more than a stop worse in terms of DOF control and high ISO (because mFT sensors have a 1 stop advantage here).

I agree that neither one of these lenses is of any use for DOF control, and the lens has nothing to do with the relative sensitivity of the sensor. Frankly most folks would be using a lens like these in situations where MORE DOF is being sought, not less. So that would give the edge to the Nikon.

Even so, the 16MP mFT sensor has an advantage of around 1 stop, so in practice the Nocti is a faster lens than the 32mm.

No, in practice, the SENSOR is faster. Not the lens.

I was not referring to depth of field, I WAS referring to light gathering - which is the same for any f1.2 lens.

How convenient that you weren't referring to DOF. DOF happens to be a very important factor for portrait lenses.

I agree, but since I find that the 45mm f1.8 to be more than sufficient in this regard (also the Sigma 60mm f2.8, which is what I actually use), therefore so is the 32mm f1.2. The Nocticron is overkill for this purpose. An frankly, it's priced at a level where as far as I'm concerned, it might as well not exist. If I actually found extremely shallow DOF to be an issue for a specific portrait requirement, I'd buy a cheap APS-C DSLR and an 85mm f1.8 lens, together (or perhaps the manual focus Samyang 85mm f1.4) for half the price of the Nocticron, rather than mis-use a small sensor camera with a ridiculously priced lens for that specific purpose, when a dedicated solution with APS-C could be had for ~ $800 or so. Or better yet, don't put money in the bank, buy full frame if this is actually the specific requirement you have. Don't mis-use a small sensor camera for a particular application that it's so ill-suited for that a freakishly expensive and ridiculously over-sized lens is the only way to make it deliver suitable results. But the proper camera for the purpose instead - and save some money in the process.

Well.......... if you're gonna use an 85mm f1.8, why not the AF-D 105 f2 or the AF-D 135 f2 with the defocuse ring? You can pretty much blur the back ground as much as you want. I know they're a bit long but putting an 85mm lens on a N1 isn't that much shorter. But of cause it's big and heavy but quality-wise would be hard to top!

Not sure that OIS is reason to justify a $700 higher price for the Noct. Maybe they sell the lenses by the ounce.

Or maybe the Nocti allows the mFT user to go one stop above the ISO a N1 users could use with the 32mm, while having equal IQ. It also has a stabilizer, which no N1 prime has. It has better DOF control and an aperture ring, which some people value.

But really, one should compare the Oly 45/1.8 to the Nikon 32/1.2, because they are essentially identical in all regards, except price. (think first, before you start the f/1.8 vs f/1.2 argument)

Again, if you want to keep on arguing this, how does the Nocticron stack up to any well chosen $800 APS-C body and 85mm f1.8 lens? It's an inferior choice, at double the price. Horses for courses, and if the specific application is extreme narrow DOF portraiture, NO small sensor camera plus lens is the optimal choice, not Nikon 1, not Micro 4/3. But the better APS-C solution for this particular need, and put $500-700 in the bank instead.

Defocus ring lenses don't reduce depth of field, they alter the quality of the out of focus areas.

DOF control depends on what you want to achieve. More depth of field is often a better form of control than less. You can blur in post processing but not the other way around.

You can stop down and use higher ISO with the bigger sensor, while still getting the same IQ like you would with the smaller sensor. There is absolutely NO advantage with the wider DOF on the smaller sensor. But there is added flexibility with the larger sensor, because you can use apply shallow DOF if you want/need it.

If you want shallow depth of field out of the camera you don't buy Nikon 1 or micro 4/3s--Have FunPhoto Pete

Maybe not N1, but there are lenses for mFT, which allow for even shallower DOF than with the NEX APSC, Nikon or Canon APSC systems. Take the Voigts 25/0.95 and 50/0.95 for example. Which lenses for Canon APSC, Nikon DX and Sony allow comparable focal length and DOF at a similar price?

In this regard only full frame is capable of beating mFT at a lower price point. But you have to live with the size and weight.